Otter and mink populations

Otters are at the top of the foodchain and so provide an important indicator of the health of our watercourses. In the 1950s and 60s otter populations crashed when watercourses became contaminated with chemicals from pesticides. Fortunately otters now seem to have returned to their original numbers on Devon’s rivers and we know that otters are now found on most watercourses in the county, but we need to keep monitoring these populations. When numbers declined drastically in the 1960s it was not until almost all the otters had gone that anyone realised the full picture. This should never happen again and ‘Otter Spotters’ now play a vital role in monitoring otter populations.

Mink (shown left) are not native to this country; they were brought to Britain at the end of the 1920s from America to be bred for their fur. They escaped from fur farms and when the otter population crashed in the 1950s they spread throughout Britain. They are highly aggressive and compete with otters for food and territory. They have been blamed for contributing to the decline in water vole populations due to predation. For these reasons, we also monitor the populations of mink as part of the operation otter survey.